A white screen, a slow page, a plugin conflict with no obvious cause, guessing your way through these wastes time. Debugging tools replace guesswork with actual data: which query is slow, which function is deprecated, which plugin is throwing the error. Here are 10 real, current options, with one dead one flagged.
Why These Tools Matter
Without real debugging data, a small problem tends to become a bigger one, someone tries a random fix, it doesn’t work, and now there are two problems instead of one. These tools show you the actual line, query, or plugin causing an issue instead of making you guess.
10 WordPress Debugging Tools
1. Query Monitor
Query Monitor is the standard tool for this: a full breakdown of database queries and how long each takes, right in an admin bar dropdown, no server access needed. Also surfaces PHP errors, HTTP requests, hooks, and enqueued scripts. The closest thing to a must-have on this list for anyone doing real theme/plugin work.
2. Debug Bar
Adds an admin bar menu with query counts, load times, and background errors. Worth a caveat: it’s community-maintained (20,000+ installs) and recent user reviews report PHP errors under newer WordPress versions, functional but worth testing on staging before relying on it heavily.
3. WP Debugging
Turns on WordPress’s built-in debug constants (WP_DEBUG, SCRIPT_DEBUG, and others) without hand-editing wp-config.php. The safest starting point if you’ve never touched debug settings directly and don’t want to risk a typo in a config file.
4. New Relic (with WordPress integration)
Server-level performance monitoring, not WordPress-specific, but genuinely useful paired with a WordPress plugin for tracking per-plugin/theme load time and server resource use. Requires a New Relic account; worth it for high-traffic sites or client work where WordPress-only tools don’t show the full picture.
5. Health Check & Troubleshooting
An overall site health report (PHP version, plugin conflicts, server settings) plus a genuinely useful Troubleshooting Mode: disables all plugins and switches to a default theme for you only, visitors see the site unaffected while you test. One of the safer tools on this list precisely because of that isolation.
6. Error Log Monitor
Free (WordPress.org, 20,000+ installs, updated within the last year, tested to WordPress 6.8). Surfaces your server error log directly in the WordPress dashboard instead of requiring hosting-panel access, with a quick-glance widget for recent errors.
7. Simple History
Logs plugin installs, logins, post edits, and settings changes. Doesn’t fix anything itself, but when something breaks after a change nobody remembers making, this is often the fastest way to find out what actually changed and when.
8. Debug Log Manager
Debug Log Manager (free, WordPress.org, 10,000+ installs, updated within the last month) gives you a readable dashboard view of your debug.log file, with filtering and clearing built in, instead of downloading and scrolling through a raw text file via FTP.
9. Debug This
Debug This adds an admin bar link for instant per-page info: which template is loading, current queries, user info. Lightweight, useful for quickly confirming which template file is actually rendering a given page.
Dropped From This List: Developer (by Automattic)
An earlier version of this post recommended “Developer” by Automattic. It was permanently closed on WordPress.org in October 2025 at the author’s own request and can no longer be installed. Query Monitor and the Health Check tool above cover the same general “set up my debugging environment properly” ground.
One More Worth Flagging: Log Deprecated Notices
This plugin (helpful for finding outdated function calls before they break) carries WordPress.org’s own “not tested with the latest 3 major releases” warning, last updated roughly 5 years ago, tested only to WordPress 5.8. Not necessarily broken, but a real risk on a current WordPress install, test on staging first if you still want to use it.
Choosing One
Query Monitor first, it covers the most ground and is actively maintained. WP Debugging or Health Check if you’re not comfortable editing config files directly. Error Log Monitor or Debug Log Manager if server error logs are specifically what you need visibility into. Simple History if you need to know who changed what, not just what broke.
Setup and Safety Notes
- Install from Plugins > Add New like any plugin; a few (WP Debugging especially) toggle settings in
wp-config.phpfor you rather than requiring manual edits. - Turn debugging off on live sites once you’re done. Exposed error messages and debug output are both a security risk and a performance drag for real visitors.